阅读说明：本技术 氧化物烧结体、溅射靶和氧化物薄膜的制造方法 (Oxide sintered body, sputtering target, and method for producing oxide thin film ) 是由 寺村享祐 深川功儿 于 2018-08-29 设计创作，主要内容包括：实施方式的一个方案的氧化物烧结体是以满足以下的式(1)～(3)的比率含有铟、镓和锌的氧化物烧结体,其由单相的晶体相构成,晶体相的平均粒径为15.0μm以下。0.01≤In/(In+Ga+Zn)＜0.20(1)；0.10≤Ga/(In+Ga+Zn)≤0.49(2)；0.50≤Zn/(In+Ga+Zn)≤0.89(3)。(An oxide sintered body according to an embodiment is an oxide sintered body containing indium, gallium, and zinc at a ratio satisfying the following formulas (1) to (3), and is composed of a single-phase crystal phase, and the average grain diameter of the crystal phase is 15.0 μm or less. 0.01 < In/(In + Ga + Zn) < 0.20 (1); Ga/(In + Ga + Zn) is more than or equal to 0.10 and less than or equal to 0.49 (2); Zn/(In + Ga + Zn) is more than or equal to 0.50 and less than or equal to 0.89 (3).)

1. An oxide sintered body containing indium, gallium and zinc at a ratio satisfying the following formulas (1) to (3), and composed of a single-phase crystal phase having an average particle diameter of 15.0 [ mu ] m or less,

0.01≤In/(In+Ga+Zn)＜0.20 (1)

0.10≤Ga/(In+Ga+Zn)≤0.49 (2)

0.50≤Zn/(In+Ga+Zn)≤0.89 (3)。

2. the oxide sintered body according to claim 1, which contains indium, gallium and zinc at a ratio satisfying the following formulas (4) to (6),

0.05≤In/(In+Ga+Zn)≤0.15 (4)

0.15≤Ga/(In+Ga+Zn)≤0.45 (5)

0.50≤Zn/(In+Ga+Zn)≤0.80 (6)。

3. the oxide sintered body according to claim 1 or 2, which contains indium, gallium and zinc at a ratio satisfying the following formulas (7) to (9),

0.05≤In/(In+Ga+Zn)≤0.15 (7)

0.20≤Ga/(In+Ga+Zn)≤0.40 (8)

0.50≤Zn/(In+Ga+Zn)≤0.70 (9)。

4. the oxide sintered body according to any one of claims 1 to 3, wherein a diffraction peak is observed in the following A to P region in a graph obtained by X-ray diffraction measurement (CuK α line) with respect to the crystal phase,

A.24.5°～26.0°

B.31.0°～32.5°

C.32.5°～33.2°

D.33.2°～34.0°

E.34.5°～35.7°

F.35.7°～37.0°

G.38.0°～39.2°

H.39.2°～40.5°

I.43.0°～45.0°

J.46.5°～48.5°

K.55.5°～57.8°

L.57.8°～59.5°

M.59.5°～61.5°

N.65.5°～68.0°

O.68.0°～69.0°

P.69.0°～70.0°。

5. the oxide sintered body according to any one of claims 1 to 4, having a relative density of 97.0% or more.

6. The oxide sintered body according to any one of claims 1 to 5, which has a flexural strength of 40MPa or more.

7. The oxide sintered body according to any one of claims 1 to 6, having a resistivity of 40m Ω -cm or less.

8. A sputtering target made of the oxide sintered body according to any one of claims 1 to 7.

9. The sputtering target according to claim 8, wherein the maximum height Ry of the surface roughness is 15.0 μm or less.

10. The sputtering target according to claim 8 or 9, which has a color difference Δ E^＊Is 10 or less.

11. A method for producing an oxide thin film, wherein the sputtering target according to any one of claims 8 to 10 is sputtered to form a film.

Technical Field

Embodiments of the present application relate to an oxide sintered body, a sputtering target, and a method for producing an oxide thin film.

Background

A sputtering method, which is a method for forming a thin film using a sputtering target, is extremely effective as a method for forming a thin film over a large area with high accuracy, and the sputtering method is widely used for display devices such as liquid crystal display devices. In the field of semiconductor layer technology of thin film transistors (hereinafter also referred to as "TFTs") and the like In recent years, an oxide semiconductor typified by an In — Ga — Zn complex oxide (hereinafter also referred to as "IGZO") has attracted attention In place of amorphous silicon, and a sputtering method has been used for forming an IGZO thin film (see, for example, patent document 1).

In this sputtering method, the following problems may occur due to the occurrence of abnormal discharge or the like: the formed thin film has abnormal quality, and a sputtering target during sputtering has cracks. One of the methods for avoiding these problems is to densify the sputtering target.

In addition, even in the case of a high-density target, abnormal discharge may occur. For example, if the crystal phase constituting the target is a complex phase (multiple phases), there is a difference in electrical resistance between different crystal phases, there is a risk that abnormal discharge occurs.

When an IGZO thin film is used as a semiconductor layer of a TFT, the semiconductor characteristics thereof greatly vary depending on the ratio of In, Ga, and Zn, and various ratios have been studied. For example, patent document 2 has studied that the ratio of each metal element is In < Ga < Zn. The In, Ga, and Zn ratios of the IGZO sputtering target can be appropriately adjusted to obtain predetermined semiconductor characteristics. For example, as an IGZO sputtering target, an IGGaZnO sputtering target was studied₄、In₂Ga₂ZnO₇The target of the homologous crystal structure shown.

On the other hand, in the case of an IGZO sputtering target containing a large amount of Zn, the sputtering target has a homologous crystal structure and Ga₂ZnO₄A target made of a complex phase of spinel structure has also been studied (for example, see patent document 3).

However, Ga₂ZnO₄Since the resistance is high as compared with a homologous crystal structure or the like, there is a large risk of abnormal discharge. Therefore, a single phase having a homologous crystal structure is preferable as the sputtering target.

On the other hand, a high-density sputtering target composed of a single phase tends to have a larger grain diameter than a sputtering target composed of a complex phase. Further, if the grain size is increased, the mechanical strength of the sputtering target is lowered, and cracking may occur during sputtering.

In addition, it is also important for the sputtering target to have uniform distribution of the above characteristics in the sputtering surface. If the density or the like is not uniformly distributed in the plane, abnormal discharge may occur, and cracks may occur during sputtering. In the case of the IGZO sputtering target, unevenness in the characteristic distribution of the sputtering surface may appear as shading of chromatic aberration.

Disclosure of Invention

Problems to be solved by the invention

Drawings

Fig. 1 is an SEM image (50 times) of the oxide sintered body in example 1.

Fig. 2 is an SEM image (500 times) of the oxide sintered body in example 1.

Fig. 3 is an SEM image (500 times) of the oxide sintered body in comparative example 2.

FIG. 4 is an X-ray diffraction chart of the oxide sintered body in example 1.

FIG. 5 is an X-ray diffraction chart of the oxide sintered body of example 1 and InGaZnO₄、In₂Ga₂ZnO₇And Ga₂ZnO₄The peak positions in the X-ray diffraction patterns of (a) are compared.

In view of the above circumstances, it is an object of an embodiment to provide a sputtering target capable of stably performing sputtering and an oxide sintered body used for manufacturing the sputtering target.

Means for solving the problems